The phonon dispersion relation of white tin has been studied with the technique of inelastic neutron scattering. Measurements were made in the (001) and (010) planes, on both a time-of-flight apparatus and a triple-axis spectrometer. Results are given along the symmetry directions. A force-constant model has been used to interpret the experimental measurements. Other theoretical work is discussed, and comparison is made of these results with superconducting tunnelling measurements. There are features in the observed dispersion curves suggesting that, as in lead, the interactions with the conduction electrons play a dominant role.